| Noun | 1. | hyaluronic acid - a viscous mucopolysaccharide found in the connective tissue space and the synovial fluid of movable joints and the humors of the eye; a cementing and protective substancesynovia, synovial fluid - viscid lubricating fluid secreted by the membrane lining joints and tendon sheaths etc. mucopolysaccharide - complex polysaccharides containing an amino group; occur chiefly as components of connective tissue | |